We propose a randomized controlled cluster designed clinical trial to evaluate the effectiveness of an innovative, tailored lifestyle intervention on overweight and obese patients in primary care practice. The study will have two phases: Phase 1 - Intervention refinement, Phase 2- Randomized design cluster clinical trial with 20 primary care providers and 200 patients. During the intervention refinement phase, focus groups of patients will inform refinement of the protocol and help adapt our intervention materials for behavioral weight loss, physical activity and dietary change. This randomized clinical trial (RCT) will compare augmented usual care to home-based lifestyle counseling of overweight/obese patients using an individually tailored intervention focusing on dietary and physical activity behavior change delivered by print and reinforced with supportive telephone counseling and video. Each PCP practice will receive obesity education via academic detailing supplemented by obesity management guideline implementation via a handheld device while the intervention PCP practices will receive in addition quarterly progress reports on behavioral goal attainments for each patient. The primary outcomes of the RCT will be change in BMI, physical activity and dietary changes at two years using an intent-to-treat analysis. Additional outcomes to be assessed for the RCT include: costs of the intervention and a cost-effectiveness evaluation by comparing the cost of the intervention per unit of BMI loss, as well as physical activity and diet change. By demonstrating the effectiveness of a practical lifestyle intervention with limited face-to-face contact for patients recruited from primary care practice that produces clinically meaningful changes in body mass index, physical activity, and healthy eating habits, the results of the proposed trial will have direct relevance to clinical practice. This study will fill an important gap in our knowledge regarding the translation and dissemination of research from efficacy studies to best practices in the community settings- an important objective of the NIH Roadmap Initiative. PUBLIC HEALTH RELEVANCE: This study is a cluster design clinical trial (RCT) that will demonstrate the effectiveness of a practical lifestyle intervention developed using state of the art behavioral science and with limited face-to-face contact for overweight/obese adult patients recruited from primary care practice that produces clinically meaningful changes in weight, physical activity, and healthy eating habits. The results of the proposed trial will have direct relevance to clinical practice. This study will fill an important gap in our knowledge regarding the translation and dissemination of research from efficacy studies to best practices in the community settings- an important objective of the NIH Roadmap Initiative.